1. Field of the Invention
The present invention relates to a method of manufacturing a magnetic head suspension assembly used to drive a magnetic disk, for instance, and more specifically to a method of manufacturing a magnetic head suspension having a circuit wiring pattern member, in which the circuit wiring pattern member for electrically connecting a magnetic head element to a read-write amplifier circuit board is formed integral with the suspension.
2. Description of the Prior Art
The magnetic disk apparatus of the type as described above is usually composed of at least one rotary disk for recording data magnetically, a magnetic head element for reading or writing data from or to each track formed on the rotary disk, and a head locating actuator for moving the magnetic head element to any desired track position and for maintaining the same magnetic head element over the track of the rotary disk.
An example of prior art magnetic head suspension assembly is disclosed in Japanese Patent Publication before examination (Kokai) No. 63-113917, in which the magnetic head element is mounted on a flexible member by use of an epoxy resin and further the flexible member is connected to a load beam by use of laser welding, for instance. Further, a gold-plated copper wire covered with polyurethane is connected to an electrode formed on the magnetic head element by use of ultrasonic welding or soldering, as a lead-out wiring portion. Further, after has been turned by a predetermined number of times, the wiring member is housed in a flexible insulating resin tube, and then mounted on the suspension by caulking a part of the suspension, for instance.
In the prior art magnetic head suspension assembly as described above, when the lead-out wire is connected to the electrode on the magnetic head element, since the connecting workability is severely restricted, the assembling work is not effective, so that the productivity cannot be improved. Further, recently, since there exists such a tendency that the magnetic head element is further small-sized and the number of terminals is further increased, this problem has become serious. In addition, since the rigidity of the lead-out wiring member exerts a harmful influence upon the floating characteristics of the magnetic head element, it has been difficult to obtain an optimum floating position or condition. In addition, since the lead-out wiring member is subjected to air pressure due to the air flow caused by the rotating recording medium, there exists another problem in that a harmful influence is exerted upon the floating position of the magnetic head element.
To overcome these problems, for instance, Japanese Patent Publication before examination (Kokai) No. 53-74414 discloses such a method that a flexible circuit board used in common for both the lead-out wiring member and the suspension is used as a supporting mechanism of the magnetic head element. In this method, however, since there are various problems with respect to the original requirements for the suspension mechanism such that the magnetic head element must be located accurately; an appropriate load must be applied; and a correct floating position must be secured, it is difficult to adopt this method in the recent high-density magnetic disk apparatus.
Therefore, in general, in order to solve the problem related to the lead-out wires, a method has been so far proposed such that the lead-out wires are connected together by use of a flexible circuit board and the circuit board is bonded onto the suspension spring by use of an adhesive for instance.
In this method, however, with increasing speed of the seek operation, in the case where the suspension is considered as having a function as a mechanical element of a servo-system, it is necessary to reduce the weight of the suspension as a composing member of the servo-system. Therefore, in the above-mentioned method such that the flexible circuit board is bonded onto the suspension spring, there arises a problem in that the weight of the suspension is inevitably increased to improve the connecting workability.
Therefore, recently, a suspension formed integral with a predetermined circuit wiring pattern via a flexible insulating base member has been proposed, as disclosed in Japanese Patent Application No. 6-193662.